Glaucoma is the leading cause of blindness in the United States. The field of glaucoma is beginning to uncover the molecular basis of this prevalent disease. The broad objective of this research is to achieve a better understanding of the factors involved in glaucomatous conditions. The goals are to delineate the trabecular meshwork-induced glucocorticoid response (TIGR) gene function within the trabecular meshwork (TM) and to elucidate the relationship between TIGR and glaucoma. This study proposes to identify protein factors associated with TIGR in the TM and to test the hypothesis that mutations in TIGR disrupt the protein's normal function, leading to development of glaucoma. The following experiments are proposed. First, factors that interact with TIGR will be identified using a powerful yeast two-hybrid technique. A TM cDNA library will be screened for factors that interact with TIGR in vivo. Interacting factors identified will be evaluated for their ability to interact with variant forms of TIGR. Second, cell biology methods such as immunohistochemical staining will be utilized to determine the localization and distribution of TIGR within the TM in normal human eyes and the variation in glaucomatous conditions. In situ hybridization will identify TIGR transcript in the human TM. Immunoprecipitation studies will also be used to investigate biochemically factors that co-precipitate with TIGR under both normal and glucocorticoid-treated conditions. This study will help us to elucidate the function of TIGR and determine specific properties of TIGR in both normal and glaucomatous conditions. This knowledge of the function, localization, and properties of the TIGR molecule is likely to be crucial in understanding how overexpression or variant forms of the molecule could produce outflow obstruction in open angle glaucomas and may lead to improve models for understanding glaucoma and new therapeutic approaches.